I was watching the improvements for years. It was typical that the moment I decided to make the change technology went into high gear.I don't use the £10,500 DCS520 now, but the 1D which has 4Mp is working its socks off. It is a little like computer speed, you don't need to have anything larger most of the time. Still, the Mk 4 has loads of appealing improvements. ASA 102,400 WHAT! Remote file transfer, HD video, 16Mp, self cleaning sensor.Just a pity people are not spending money to enable an upgrade.